This invention relates to a paper feeder for a printer for feeding to a printing mechanism portion one at a time paper sheets which are stacked on a paper holder.
A known device of the type described above is disclosed in Japanese Patent Laid-Open No. 60-61436.
In this conventional device, a paper feed roller is provided in such a manner that it is arranged to be positioned in contact with the front end of paper sheets stacked on a paper holder. Furthermore a friction pad for separating paper sheets from each other is forcedly positioned in contact with the paper feed roller so that when a first paper sheet is fed in association with the rotation of the paper feed roller, simultaneous feeding of a second sheet is prevented by means of the friction pad.
In such a conventional device of the type described above, the upper surface of a first paper sheet which has been inserted is held by a paper feed roller by means of its frictional force in the place where the paper feed roller and the friction pad are positioned in contact with each other. Furthermore, the lower surface of the inserted second paper sheet is held by the friction pad by means of its frictional force so as to overcome the frictional force between the two sheets, thereby allowing only the first paper sheet to be fed in association with the rotation of the paper feed roller.
However, in such a conventional device, since the friction pad is always positioned in forced contact with the paper feed roller at a same position of the friction pad, the friction pad becomes worn and paper dust accumulates on the friction pad. As a result of this, the frictional force becomes gradually poorer, causing the paper separation performance to deteriorate and eventually two or more paper sheets are inevitably fed together.
Furthermore, when only a first paper sheet, rather than the first and the second paper sheets together, of a multiplicity of paper sheets stacked on a paper holder is inserted into the portion at which the paper feed roller and the friction pad are positioned in contact with each other, both the frictional force of the paper feed roller and the frictional force of the friction pad are simultaneously applied to the first paper sheet. As a result of this, the first paper sheet is captured by the friction pad and this prevents the paper feed from occurring properly.